Important information for people using Tirzepatide (Mounjaro®) and other GLP1 medicines e.g. Semaglutide (Ozepmic®, Wegovy®, Rybelsus®) for weight loss
Many patients are now using weight loss medications like Tirzepatide (Mounjaro®) or Semaglutide (Ozempic®, Wegovy®, Rybelsus®) — either via NHS prescriptions for diabetes, or via a private prescription for weight loss.
These medications work partly by slowing down how your stomach empties- which can affect how well other medicines (like the contraceptive pill or HRT tablets) are absorbed by the body.
Important information for patients with who could become pregnant
Mounjaro® and GLP1 injections should not be taken during pregnancy as it is not known what impact these may have on a developing baby. If you are under the age of 55 years you should ensure that you do not become pregnant while using these medicines.
Please make an appointment for a contraceptive review if you are using these medicines and you are not using contraception.
If you are planning a pregnancy you will need to stop using these injections for a few months BEFORE you start trying for a baby. You can see how many months you need to be off these injections at Patient-information-GLP-1-agonists-and-contraception.pdf
This includes
- ONE month before for Tirzepatide (Mounjaro®)
- TWO months before for Semaglutide (Ozepmic®, Wegovy®, Rybelsus®
Important notice for patients using weight loss medications and taking the contraceptive pill
If you are using an oral contraceptive to prevent a pregnancy, then please be aware that these medicines can reduce the efficacy of your contraceptive. Please read this document from the Faculty of Sexual & Reproductive Healthcare on this subject.
The key points are:
- If you are using Tirzepatide (Mounjaro)®
- You should use a barrier method of contraception (e.g. condoms) in addition to your pill for four weeks after starting the medication, and for four weeks after any increase in dose.
- If you vomit or have diarrhoea within 3 hours of taking your contraceptive pill, or if you have diarrhoea for more than 24 hours, you should follow the missed pill rules in the patient information leaflet that comes with your pill. You should also use barrier contraception (e.g. condoms)
- If you are using Semaglutide (Ozempic®, Wegovy®, Rybelsus®)
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- Semaglutide does not appear to reduce the effectiveness of the pill, but side effects like vomiting or diarrhoea can still reduce how well the pill is absorbed.
- If you vomit or have diarrhoea within 3 hours of taking your contraceptive pill, or if you have diarrhoea for more than 24 hours, you should follow the missed pill rules in the patient information leaflet that comes with your pill. You should also use barrier contraception (e.g. condoms)
- If you are switching to Mounjaro® from any other GLP-1 agonist then you should use a barrier method of contraception (such as a condom) for four weeks after the switch, and for four weeks after any increases in dose, while also continuing your oral contraception.
- We don’t know yet if oral emergency contraception is affected by GLP-1 agonists.
If you’re taking Hormone Replacement Therapy (HRT):
This applies if your HRT includes progesterone tablets like:
- Micronized Progesteron (Utrogestan® or Gepretix®)
- Norethisterone (Noriday®, Primolut N® or Utovlan®)
- Medroxyprogesterone acetate (Provera®)
There is some concern that weight loss medications – such as Tirzepatide (Mounjaro®) and Semaglutide (Ozempic®, Wegovy®, Rybelsus®) – may reduce how well these progesterone tablets are absorbed.
This could lower your progesterone level in your body, lead to irregular vaginal bleeding and may affect the protection of your womb lining, potentially leading to an increased risk of endometrial (womb) cancer.
There is limited evidence on how likely this is, and the best action to take to reduce this risk. We know that being overweight can also increase your risks of endometrial cancer as well as cardiovascular diseases.
Experts have made the recommendations below:
- First choice: Use a non-oral progesterone e.g. Mirena coil (IUS)
- Please contact us to arrange an appointment to discuss this
- This works for 5 years as part of HRT and is also a contraceptive
- Consider a combined HRT patch
- This contains both oestrogen and progesterone and is absorbed through the skin and so bypasses the stomach.
- These are only available in fixed dose combinations.
- If the above options are not suitable for you, we may consider increasing your progesterone dose temporarily for the 4 weeks after starting a GLP1, and 4 weeks after increasing the dose.
Please contact the surgery to arrange to discuss these options for you
